Wireless communication method and wireless communication device

ABSTRACT

The present disclosure provides wireless communication methods for repeated transmission of channels, and wireless communication devices therefor. In one embodiment, the gap between the starting subframe of a first channel and the starting subframe of a second channel is defined or configured. In another embodiment, Mx*W=M and Mx*n=N is satisfied, where Mx is the number of subframes reserved for the channel in one HARQ process, M is RTT for one HARQ process, W is a positive integer and represents the maximum number of HARQ processes transmitting the channel within M subframes, N is the gap between the starting subframes of the channel in two HARQ processes, and n is a positive integer. In yet another embodiment, time-frequency resources for the channel in different HARQ processes are different.

BACKGROUND

1. Technical Field

The present disclosure relates to the field of wireless communication,and in particular, to wireless communication methods for repeatedtransmission/reception of channels (channel repetitions), and wirelesscommunication devices such as eNode B (eNB) and user equipment (UE).

2. Description of the Related Art

Machine-Type Communication (MTC) is an important revenue stream foroperators and has a huge potential from the operator's perspective.Based on the market and operators' requirements, one of the importantrequirements of MTC is improving the coverage of MTC UEs. To enhance theMTC coverage, almost each of the physical channels needs to be enhanced.And the repeated transmission/reception in time domain is the mainmethod to improve the coverage of the channels. The repeatedtransmission/reception is to repeatedly transmit/receive a channel or torepeatedly transmit/receive a signal on the channel, the channel or thesignal on the channel, which is repeatedly transmitted/received, isreferred as the channel repetitions. And to satisfy multiple differentcoverage requirements, multiple repetition levels can be supported whileeach of the repetition level corresponds to one or multiple integralrepetition numbers. The repetition number is a number of repetitions ofthe channel in the repeated transmission. Each of the repetitions willbe transmitted in one subframe; therefore, multiple subframes will beused for transmitting the repetitions of the channel.

For uplink (UL) and downlink (DL) data transmission, HARQ (HybridAutomatic Repeat Request) process can be used. In each HARQ process,control channel and data channel are included, and sometimes a feedbackchannel (ACK/NACK channel) for the data packet can also be included. Thecontrol channel carries the scheduling information of the data packet.The data channel carries the data packet and is transmitted in the wayindicated by the control channel. When the receiver received the datapacket and decoded it successfully, information of ACK (Acknowledgement)is transmitted to the data transmitter to inform the successfuldecoding. Otherwise, NACK (Negative-Acknowledgement) is transmitted.

SUMMARY

In view of the above, one non-limiting and exemplary embodimentfacilitates providing wireless communication methods for repeatedtransmission of channels, and wireless communication devices such as eNBor UE.

In a first general aspect of the present disclosure, there is provided awireless communication method performed by a first wirelesscommunication device, comprising: transmitting or receiving channelrepetitions of a first channel in multiple subframes to or from a secondwireless communication device; and transmitting or receiving channelrepetitions of a second channel in multiple subframes to or from thesecond wireless communication device, wherein a gap between a startingsubframe of the first channel and a starting subframe of the secondchannel is defined or configured.

According to the first general aspect of the present disclosure, thestarting subframe of a second channel following a first channel can bedetermined regardless of the repetition number used by the firstchannel.

In a second general aspect of the present disclosure, there is provideda wireless communication method performed by a first wirelesscommunication device, comprising: transmitting or receiving channelrepetitions of channel in multiple subframes to or from a secondwireless communication device in multiple hybrid automatic repeatrequest (HARQ) processes, wherein Mx*W=M, where Mx is the number ofsubframes reserved for the channel in one HARQ process, M is Round TripTime (RTT) for one HARQ process, and W is a positive integer andrepresents the maximum number of HARQ processes within M subframes; andMx*n=N, where N is a gap between starting subframes of the channel intwo HARQ processes, and n is a positive integer.

According to the second general aspect of the present disclosure,resource collision of a channel among different HARQ processes can beavoided.

In a third general aspect of the present disclosure, there is provided awireless communication method performed by a first wirelesscommunication device, comprising: transmitting or receiving channelrepetitions of a channel in multiple subframes to or from a secondwireless communication device in multiple hybrid automatic repeatrequest (HARQ) processes, wherein time-frequency resources for thechannel in different HARQ processes are different.

According to the third general aspect of the present disclosure,resource collision of a channel among different HARQ processes can beavoided.

In a fourth general aspect of the present disclosure, there is provideda wireless communication device, comprising: a first communication unitconfigured to transmit or receive channel repetitions of a first channelin multiple subframes to or from a second wireless communication device;and a second communication unit configured to transmit or receivechannel repetitions of a second channel in multiple subframes to or fromthe second wireless communication device, wherein a gap between astarting subframe of the first channel and a starting subframe of thesecond channel is defined or configured.

According to the fourth general aspect of the present disclosure, thestarting subframe of a second channel following a first channel can bedetermined regardless of the repetition number used by the firstchannel.

In a fifth general aspect of the present disclosure, there is provided awireless communication device, comprising: a communication unitconfigured to transmit or receive channel repetitions of a channel inmultiple subframes to or from a second wireless communication device inmultiple hybrid automatic repeat request (HARQ) processes, whereinMx*W=M, where Mx is the number of subframes reserved for the channel inone HARQ process, M is Round Trip Time (RTT) for one HARQ process, and Wis a positive integer and represents the maximum number of HARQprocesses transmitting the channel within M subframes; and Mx*n=N, whereN is a gap between starting subframes of the channel in two HARQprocesses, and n is a positive integer.

According to the fifth general aspect of the present disclosure,resource collision of a channel among different HARQ processes can beavoided.

In a sixth general aspect of the present disclosure, there is provided awireless communication device, comprising: a communication unitconfigured to transmit or receive channel repetitions of a channel inmultiple subframes to or from a second wireless communication device inmultiple hybrid automatic repeat request (HARQ) processes, whereintime-frequency resources for the channel in different HARQ processes aredifferent.

According to the sixth general aspect of the present disclosure,resource collision of a channel among different HARQ processes can beavoided.

The foregoing is a summary and thus contains, by necessity,simplifications, generalization, and omissions of details. Otheraspects, features, and advantages of the devices and/or processes and/orother subject matters described herein will become apparent in theteachings set forth herein. The summary is provided to introduce aselection of concepts in a simplified form that are further describedbelow in the Detailed Description. This summary is not intended toidentify key features or essential features of the claimed subjectmatter, nor is it intended to be used as an aid in determining the scopeof the claimed subject matter.

It should be noted that general or specific embodiments may beimplemented as a system, a method, an integrated circuit, a computerprogram, a storage medium, or any selective combination thereof.

Additional benefits and advantages of the disclosed embodiments willbecome apparent from the specification and drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the specification and drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present disclosure will becomemore fully apparent from the following description and appended claims,taken in conjunction with the accompanying drawings. Understanding thatthese drawings depict only several embodiments in accordance with thedisclosure and are, therefore, not to be considered limiting of itsscope, the disclosure will be described with additional specificity anddetail through use of the accompanying drawings, in which:

FIG. 1 schematically illustrates a HARQ process chart;

FIG. 2 illustrates a flowchart of a wireless communication method forrepeated transmission of channels according to an embodiment of thepresent disclosure;

FIG. 3 schematically illustrates the gaps between the starting subframesof the first channel and the starting subframes of the second channelfor three exemplary repetition numbers of the first channel;

FIG. 4 is a block diagram illustrating a wireless communication devicefor repeated transmission of channels according to an embodiment of thepresent disclosure;

FIG. 5 illustrates an exemplary resource collision in which therepetitions of (E)PDDCH in the first HARQ process is collided with therepetitions of the (E)PDDCH in the fourth HARQ process;

FIG. 6 illustrates a flowchart of a wireless communication method forrepeated transmission of a channel according to an embodiment of thepresent disclosure;

FIG. 7 illustrates exemplary DL HARQ processes for avoiding the resourcecollision of the control channel;

FIG. 8 illustrates exemplary DL HARQ processes for avoiding the resourcecollision of the data channel;

FIG. 9 illustrates exemplary DL HARQ processes for avoiding the resourcecollision of the ACK/NACK channel;

FIG. 10 illustrates exemplary UL HARQ processes for avoiding theresource collision of the control channel;

FIG. 11 illustrates exemplary UL HARQ processes for avoiding theresource collision of the data channel;

FIG. 12 illustrates exemplary UL HARQ processes for avoiding theresource collision of the ACK/NACK channel;

FIG. 13 is a block diagram illustrating a wireless communication devicefor repeated transmission of a channel according to an embodiment of thepresent disclosure;

FIG. 14 illustrates a flowchart of a wireless communication method forrepeated transmission of a channel according to an embodiment of thepresent disclosure;

FIG. 15 is a block diagram illustrating a wireless communication devicefor repeated transmission of a channel according to an embodiment of thepresent disclosure; and

FIG. 16 illustrates an exemplary association of the time-frequencyresources and the starting subframes of HARQ processes for (E)PDCCH.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part thereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. It will be readily understood that the aspects ofthe present disclosure can be arranged, substituted, combined, anddesigned in a wide variety of different configurations, all of which areexplicitly contemplated and make part of this disclosure.

It is noted that although the embodiments of the present disclosure maybe described in the context of MTC, the present disclosure can beapplied to any communication which needs channel repetitions. Inaddition, in the present disclosure, the term of “wireless communicationdevice” refers an eNB and a UE depending on different scenarios. Forexample, for an UL HARQ process, the wireless communication fortransmitting the control channel and receiving the data channel is aneNB, and the wireless communication for receiving the control channeland transmitting the data channel is a UE.

In one HARQ process which may be uplink or downlink, at least a controlchannel and a data channel are included. In additional, a channelcarrying ACK or NACK may also be included. As shown in FIG. 1 whichschematically illustrates a HARQ process, the number of subframesreserved for the control channel, the scheduled data channel (or simplyreferred to as data channel) and the corresponding ACK/NACK channel areM1, M2 and M3, respectively. The gap between the control channelsubframes and the scheduled data channel subframes is I subframes. Thegap between the scheduled data channel and the corresponding ACK/NACKchannel subframes is J subframes. The gap between the ACK/NACK channelsubframes and the next candidate of control channel in this HARQ processis K subframes. Wherein

M1 and M2 are positive integers, and I, J, K, M3 are integers not lessthan zero. When M3=0, there is no specific ACK/NACK channel for the datatransmission. M is Round Trip Time (RTT) for one HARQ process. RTT isthe time it takes for a transmitter to send a request and the receiverto send a response back to the transmitter. In particular, RTT can bethe gap between two starting subframes of a channel (e.g. controlchannel) in the same HARQ process, i.e., the gap between the startingsubframe of a candidate of a channel and the starting subframe of thenext candidate of the channel in the same HARQ process. Alternatively,RRT can also be defined as M=M1+M2+M3+1+J+K.

As described in the above, channel repetition in time domain (i.e.repeated transmission of a channel) can be used to improve the coverageof the channels. Each of the repetitions of a channel (channelrepetitions) will be transmitted in one subframe, and thus multiplesubframes will be used for transmitting the repetitions of the channel.When one or more channels in one HARQ process are transmittedrepeatedly, i.e. channel repetitions are applied, the starting subframesof the repetitions of the channels needs to be defined.

First Embodiment

The repetition of a channel such as the control channel can bedynamically changed according to the channel state, schedulingsituation, etc. There is big probability that the repetition number isblindly detected. The repetition number ambiguity may lead to thestarting subframe of the following channel unknown. For example, thedata channel should be started after successful decoding ofcorresponding control channel, and then the receiver can know the exactresources for the data channel. However, when the repetition of controlchannel is dynamically changed according to the channel state,scheduling situation, etc., the receiver cannot know the exact startingof the data channel's repetitions.

In order to solve this issue, an embodiment of the present disclosureprovides a wireless communication method 200 performed by a firstwireless communication device for repeated transmission of channels, asshown in FIG. 2 which illustrates a flowchart of the wirelesscommunication method 200. Here, the first wireless communication deviceis a UE or eNB according to different scenarios. When the first wirelesscommunication device is a UE, the second wireless communicationdescribed later is an eNB, and vice versa.

The method 200 comprises a step 201 of transmitting or receiving channelrepetitions of a first channel in multiple subframes to or from a secondwireless communication device, and a step 202 of transmitting orreceiving channel repetitions of a second channel in multiple subframesto or from the second wireless communication device. Here, the firstchannel and the second channel can be any of the control channel, thedata channel and the feedback channel respectively, and the transmissionof the first channel is followed by the transmission of the secondchannel. The method 200 can be applied to both UL and DL. For example,assume that the first channel is the control channel and the secondchannel is the data channel, for a DL transmission, when the firstwireless communication device is an eNB, the step 201 would be that thefirst wireless device (eNB) transmits channel repetitions of the firstchannel (control channel) in multiple subframes to the second wirelesscommunication device (UE), and the step 202 would be that the firstwireless device (eNB) transmits channel repetitions of the secondchannel (data channel) in multiple subframes to the second wirelesscommunication device (UE); when the first wireless communication deviceis a UE, the step 201 would be that the first wireless device (UE)receives channel repetitions of the first channel (control channel) inmultiple subframes from the second wireless communication device (eNB),and the step 202 would be that the first wireless device (UE) receiveschannel repetitions of the second channel (data channel) in multiplesubframes from the second wireless communication device (eNB). For a ULtransmission, when the first wireless communication device is an eNB,the step 201 would be that the first wireless device (eNB) transmitschannel repetitions of the first channel (control channel) in multiplesubframes to the second wireless communication device (UE), and the step202 would be that the first wireless device (eNB) receives channelrepetitions of the second channel (data channel) in multiple subframesfrom the second wireless communication device (UE); when the firstwireless communication device is a UE, the step 201 would be that thefirst wireless device (UE) receives channel repetitions of the firstchannel (control channel) in multiple subframes from the second wirelesscommunication device (eNB), and the step 202 would be that the firstwireless device (UE) transmits channel repetitions of the second channel(data channel) in multiple subframes to the second wirelesscommunication device (eNB).

In order to get knowledge of the starting subframe of the second channelfollowing the first channel, in this embodiment, the gap between thestarting subframe of the first channel and the starting subframe of thesecond channel is defined or configured. Therefore, both the firstwireless communication device and the second wireless communicationdevice can know the starting subframe of the second channel. Here, theterm of “define” means the way of determining the gap or the value ofthe gap is fixedly set in the first and second wireless communicationdevices and cannot change during the communication, for example, isdetermined by the specification. The term of “configure” means the wayof determining the gap or the value of the gap is signaled by signaling,for example by physical, MAC or RRC signaling. In the following, theways of determining the gap are described in detail by examples.

In a first example, the gap between the starting subframe of the firstchannel and the starting subframe of the second channel can be the samein one HARQ process for one UE regardless of the repetition number andthe starting subframe of the first channel. FIG. 3 schematicallyillustrate the gaps between the starting subframe of the first channeland the starting subframe of the second channel for three exemplaryrepetition numbers of the first channel. As shown in FIG. 3, even thoughthe three repetition numbers are different and the starting subframes ofthe three repetition numbers are also different, the gaps are the same,all are r subframes. Therefore, the receiver (UE or eNB) can know thestarting subframe of the second channel independently from therepetition number of the first channel. For example, when the firstchannel is (E)PDCCH and the second channel is PDSCH (Physical DownlinkShared Channel), the receiving UE can know the starting subframe ofPDSCH independently from repetition number of (E)PDCCH.

In a second example, the gap between the starting subframe of the firstchannel and the starting subframe of the second channel can beassociated with the maximum repetition number defined or configured forthe first channel between the first wireless communication device andthe second wireless communication device. From system's perspective,there are multiple repetition levels, and each repetition level includesat least one repetition number for one type of channel, i.e. multiplerepetition numbers can be supported in each repetition level. Therefore,there can be at least two possibilities for transmitting channelrepetitions. Firstly, a transmitter can transmit a channel by anyrepetition level, in other words, a channel can be transmitted with anyrepetition number of any repetition level. Therefore, it is possible forthe transmitter to transmit the channel by the maximum repetition numberof all the repetition levels. In this case, the gap can be associatedwith the maximum repetition number of all the repetition levels, forexample, the gap can be the same as or larger than the maximumrepetition number of all the repetition levels. Secondly, in a certainperiod, a transmitter can transmit a channel only by a repetition numberwithin one repetition level. In this case, for one UE in one period, thechannel can possibly be transmitted by the maximum repetition numberwithin the one repetition level configured or defined for the UE.Therefore, the gap can be determined by (i.e. associated with) eachrepetition level or the maximum repetition number within each repetitionlevel. For example, the gap can be the same as or larger than themaximum repetition number within each repetition level. It is noted thatthe period here can be any period, even the whole operation lifetime, inother words, for one UE, some channel can be transmitted always by onerepetition level. Take Table 1 as an example, repetition level R1, R2and R3 correspond to gap value g1, g2, and g3, respectively. Forexample, when the repetition level is determined to be R1, the gap is g1which can be the same as or larger than R1 assuming R1 represents themaximum repetition number of the repetition level R1.

TABLE 1 Repetition level Gap value (subframe) R1 g1 R2 g2 R3 g3

It is noted that the maximum repetition number defined or configured forthe first channel between the first wireless communication device andthe second wireless communication device in the second example comprisesthe above two cases, i.e., the maximum repetition number of all therepetition levels and the maximum repetition number within the onerepetition level configured or defined for the UE, since both themaximum repetition numbers are the maximum repetition number defined orconfigured for the first channel between the first wirelesscommunication device and the second wireless communication device.

In the first embodiment, a wireless communication device for performingthe above method is also provided. FIG. 4 is a block diagramillustrating a wireless communication device 400 for repeatedtransmission of channels according to an embodiment of the presentdisclosure. The device 400 comprises: a first communication unit 401(transceiver, a transmitter or a receiver) configured to transmit orreceive channel repetitions of a first channel in multiple subframes toor from a second wireless communication device; and second communicationunit 402 (transceiver, transmitter or receiver) configured to transmitor receive channel repetitions of a second channel in multiple subframesto or from the second wireless communication device, wherein the gapbetween the starting subframe of the first channel and the startingsubframe of the second channel is defined or configured.

The wireless communication device 400 according to the presentdisclosure may optionally include a CPU (Central Processing Unit) 410for executing related programs to process various data and controloperations of respective units in the wireless device 400, a ROM (ReadOnly Memory) 413 for storing various programs required for performingvarious process and control by the CPU 410, a RAM (Random Access Memory)415 for storing intermediate data temporarily produced in the procedureof process and control by the CPU 410, and/or a storage unit 417 forstoring various programs, data and so on. The above communication unit401, CPU 410, ROM 413, RAM 415 and/or storage unit 417 etc. may beinterconnected via data and/or command bus 420 and transfer signalsbetween one another.

Respective units as described above do not limit the scope of thepresent disclosure. According to one implementation of the disclosure,the functions of the above first communication unit 401 and secondcommunication unit 402 may be implemented by hardware, and the above CPU410, ROM 413, RAM 415 and/or storage unit 417 may not be necessary.Alternatively, the functions of the above first communication unit 401and second communication unit 402 may also be implemented by functionalsoftware in combination with the above CPU 410, ROM 413, RAM 415 and/orstorage unit 417 etc.

According to the first embodiment of the present disclosure, thestarting subframe of a second channel following a first channel can bedetermined regardless of the repetition number used by the firstchannel.

Second Embodiment

In repeated transmission of a channel, when there are multiple differentHARQ processes, the control channels (or data channels or feedbackchannels) of multiple HARQ processes may overlap. The overlap may causeresource efficiency reduction or resource collision. For example, whenthe collision channel is (E)PDCCH, it means there are multiple (E)PDCCHsfor DL grant to one UE in one subframe, which will increase the resourceblocking probability in (E)PDCCH search space. FIG. 5 illustrates anexemplary resource collision in which the repetitions of (E)PDDCH in thefirst HARQ process is collided with the repetitions of the (E)PDDCH inthe fourth HARQ process. When the collision channel is PDSCH or PUSCH(Physical Uplink Shared Channel), it means there are multiple datapackets transmitted in one subframe for one UE. It needs multiple piecesof control signaling to inform the scheduling information, which is awaste of control channel. When the collision channel is the channelcarrying ACK/NACK, the resource collision may cause the ACK/NACK notreceived correctly. It is noted that, in the present disclosure,“different HARQ processes” does not mean that the HARQ processes musthave different indexes, but mean that the HARQ processes are startedseparately and they may have the same index or different indexes. Forexample, in FIG. 5, the 1^(st), 2^(nd), 3^(rd), 4^(th) HARQ processesare different HARQ processes which are started separately in differentstarting subframes, but they may have the same index or differentindexes.

In order to solve this issue, an embodiment of the present disclosureprovides a wireless communication method 600 performed by a firstwireless communication device for repeated transmission of a channel, asshown in FIG. 6 which illustrates a flowchart of the wirelesscommunication method 600. Here, the first wireless communication devicecan be a UE or eNB. When the first wireless communication device is aUE, the second wireless communication described later is an eNB, andvice versa.

The method 600 can comprise a step 601 of transmitting or receivingchannel repetitions of the channel in multiple subframes to or from asecond wireless communication device in multiple HARQ processes. Similarto the first embodiment, the method 600 can be applied to both UL andDL. The channel can be any one of a control channel, a scheduled channeland an ACK/NCK channel.

In the second embodiment, Mx*W=M is satisfied, where Mx is the number ofsubframes reserved for the channel in one HARQ process, M is Round TripTime (RTT) for one HARQ process, and W is a positive integer andrepresents the maximum number of HARQ processes transmitting the channelwithin M subframes. In addition, Mx*n=N is also satisfied in the secondembodiment, where N is the gap between the starting subframes of thechannel in two HARQ processes, and n is a positive integer. The detaileddescription of Mx and M can refer to the description with reference toFIG. 1, which will not be repeated here. According to the secondembodiment, the repetitions of a channel in one HARQ process will notoverlap the repetitions of the channel in another HARQ process.

In the following, the second embodiment will be described in detailthrough several examples.

In a first example as shown in FIG. 7, exemplary DL HARQ processes areillustrated for avoiding the resource collision of the control channel.For a DL HARQ process, the control channel and data channel are PDCCH orEPDCCH ((E)PDCCH) and PDSCH respectively, and the ACK/NACK channel isPUCCH (Physical Uplink Control Channel) or PUSCH. For a DL HARQ process,I=0 where I is the gap between the control channel subframes and thescheduled data channel subframes as shown in FIG. 1. In this example,the solution is used to avoid the resource collision of the controlchannel among DL HARQ processes of one UE. As shown in FIG. 7, M1 is thenumber of subframes reserved for PDCCH or EPDCCH, wherein M1*W=M andM1*n=N. In the figure, W=4 (i.e., 4M1=M), which is just an example. Byusing the solution, there is no resource collision of the controlchannel among the HARQ processes.

In a second example as shown in FIG. 8, exemplary DL HARQ processes areillustrated for avoiding the resource collision of the data channelamong DL HARQ processes of one UE. As shown in FIG. 8, M2 is the numberof subframes reserved for PDSCH, wherein M2*W=M and M2*n=N. In thefigure, W=4 (i.e., 4M2=M), which is just an example. By using thesolution, there is no resource collision of the data channel among theHARQ processes.

In a third example as shown in FIG. 9, exemplary DL HARQ processes areillustrated for avoiding the resource collision of the ACK/NACK channelamong DL HARQ processes of one UE. As shown in FIG. 9, M3 is the numberof subframes reserved for PUCCH or PUSCH, wherein M3*W=M and M3 n=N. Inthe figure, W=4 (i.e., 4M3=M), which is just an example. By using thesolution, there is no resource collision of the ACK/NACK channel amongthe HARQ processes.

In the above first to third examples, the DL HARQ processes aredescribed, while in the following fourth to sixth examples, the DL HARQprocesses will be described. For a UL HARQ process, the control channeland the data channel are (E)PDCCH and PUSCH respectively, and theACK/NACK channel is Physical Hybrid-ARQ Indicator Channel (PHICH). For aUL HARQ process, I=0. For UL data transmission, there are two possiblecases to trigger retransmission:

Case 1: Triggered by PHICH+(E)PDCCH, which means that PHICH will carrythe ACK/NACK of UL data, but it can be overridden by the NDI(New DataIndicator) in DCI carried by PDCCH or EPDCCH. As a result, the wholeprocedure of one UL data transmission includes (E)PDCCH, PUSCH andPHICH.

Case 2: Triggered by (E)PDCCH or EPDCCH, which means no need to transmitPHICH. Therefore, (E)PDCCH and PUSCH are enough in the whole HARQprocedure.

In the fourth example as shown in FIG. 10, exemplary UL HARQ processesare illustrated for avoiding the resource collision of the controlchannel among UL HARQ processes of one UE. As shown in FIG. 10, M1 isthe number of subframes reserved for PDCCH or EPDCCH, wherein M1*W=M andM1*n=N. In the figure, W=5 (Case 1) or 4 (Case 2), which is only anexample. By using the solution, there is no resource collision of thecontrol channel among the UL HARQ processes.

In the fifth example as shown in FIG. 11, exemplary UL HARQ processesare illustrated for avoiding the resource collision of the data channelamong UL HARQ processes of one UE. As shown in FIG. 11, M2 is the numberof subframes reserved for PUSCH, wherein M1*W=M and M1*n=N. In thefigure, W=5 (Case 1) or 4 (Case 2), which is only an example. By usingthe solution, there is no resource collision of the data channel amongthe UL HARQ processes.

In the sixth example as shown in FIG. 12, exemplary UL HARQ processesare illustrated for avoiding the resource collision of PHICH among ULHARQ processes of one UE. As shown in FIG. 12, M3 is the number ofsubframes reserved for PHICH, wherein M3*W=M and M1*n=N. In the figure,W=5, which is only an example. By using the solution, there is noresource collision of PHICH among the UL HARQ processes.

In the second embodiment, a wireless communication device for performingthe above method is also provided. FIG. 13 is a block diagramillustrating a wireless communication device 1300 for repeatedtransmission of a channel according to an embodiment of the presentdisclosure. The device 1300 comprises: a communication unit 1301(transceiver, transmitter or receiver) configured to transmit or receivechannel repetitions of the channel in multiple subframes to or from asecond wireless communication device in multiple hybrid automatic repeatrequest (HARQ) processes, wherein Mx*W=M is satisfied, where Mx is thenumber of subframes reserved for the channel in one HARQ process, M isRound Trip Time (RTT) for one HARQ process, and W is a positive integerand represents the maximum number of HARQ processes transmitting thechannel within M subframes; and Mx*n=N, where N is the gap between thestarting subframes of the channel in two HARQ processes, and n is apositive integer.

The wireless communication device 1300 according to the presentdisclosure may optionally include a CPU (Central Processing Unit) 1310for executing related programs to process various data and controloperations of respective units in the wireless device 1300, a ROM (ReadOnly Memory) 1313 for storing various programs required for performingvarious process and control by the CPU 1310, a RAM (Random AccessMemory) 1315 for storing intermediate data temporarily produced in theprocedure of process and control by the CPU 1310, and/or a storage unit1317 for storing various programs, data and so on. The abovecommunication unit 1301, CPU 1310, ROM 1313, RAM 1315 and/or storageunit 1317 etc. may be interconnected via data and/or command bus 1320and transfer signals between one another.

Respective units as described above do not limit the scope of thepresent disclosure. According to one implementation of the disclosure,the functions of the above communication unit 1301 may be implemented byhardware, and the above CPU 1310, ROM 1313, RAM 1315 and/or storage unit1317 may not be necessary. Alternatively, the functions of the abovecommunication unit 1301 may also be implemented by functional softwarein combination with the above CPU 1310, ROM 1313, RAM 1315 and/orstorage unit 1317 etc.

According to the second embodiment, resource collision of a channelamong different HARQ processes can be avoided.

Third Embodiment

The third embodiment provides an alternative way to solve the problem ofresource collision of a channel among different HARQ processes asdescribed in the above. There can be more than one time-frequencyresources for transmitting signals of each channel in one subframe, andthese time-frequency resources are orthogonal. Therefore, when differentHARQ processes use different time-frequency resources within a subframeto transmit repetitions of a channel, the resources for the channel indifferent HARQ processes will not collide even when the subframes theyuse overlap. For example, the resource for DCIs of different HARQprocesses can be different in one control channel domain, which can beused to avoid the resource collision of (E)PDCCH.

In view of the above, the third embodiment provides a wirelesscommunication method 1400 performed by a first wireless communicationdevice for repeated transmission of a channel, as shown in FIG. 14 whichillustrates a flowchart of the wireless communication method 1400. Themethod 1400 can comprise a step 1401 of transmitting or receivingchannel repetitions of the channel in multiple subframes to or from asecond wireless communication device in multiple HARQ processes, whereintime-frequency resources for the channel in different HARQ processes aredifferent. Similar to the first and second embodiments, the method 1400can be applied to both UL and DL. The channel can be any one of acontrol channel, a scheduled channel and a corresponding ACK/NCKchannel. Assuming the channel is the control channel, the PDCCH orEPDCCH of different HARQ processes for one UE can be mapped ontodifferent resources or candidates in the control region in one subframe.For example, PDCCH or EPDCCH of 1^(st) HARQ process is mapped onto1^(st) candidate and PDCCH or EPDCCH of 2^(nd) HARQ process is mappedonto 2^(nd) candidate.

In the third embodiment, a wireless communication device for performingthe above method is also provided. FIG. 15 is a block diagramillustrating a wireless communication device 1500 for repeatedtransmission of a channel according to an embodiment of the presentdisclosure. The device 1500 comprises: a communication unit 1501(transceiver, transmitter or receiver) configured to transmit or receivechannel repetitions of the channel in multiple subframes to or from asecond wireless communication device in multiple hybrid automatic repeatrequest (HARQ) processes, wherein time-frequency resources for thechannel in different HARQ processes are different.

The wireless communication device 1500 according to the presentdisclosure may optionally include a CPU (Central Processing Unit) 1510for executing related programs to process various data and controloperations of respective units in the wireless device 1500, a ROM (ReadOnly Memory) 1515 for storing various programs required for performingvarious process and control by the CPU 1510, a RAM (Random AccessMemory) 1515 for storing intermediate data temporarily produced in theprocedure of process and control by the CPU 1510, and/or a storage unit1517 for storing various programs, data and so on. The abovecommunication unit 1501, CPU 1510, ROM 1513, RAM 1515 and/or storageunit 1517 etc. may be interconnected via data and/or command bus 1520and transfer signals between one another.

Respective units as described above do not limit the scope of thepresent disclosure. According to one implementation of the disclosure,the functions of the above communication unit 1501 may be implemented byhardware, and the above CPU 1510, ROM 1513, RAM 1515 and/or storage unit1517 may not be necessary. Alternatively, the functions of the abovecommunication unit 1501 may also be implemented by functional softwarein combination with the above CPU 1510, ROM 1513, RAM 1515 and/orstorage unit 1517 etc.

Further, in order to determine the resources or candidates for a channel(e.g. (E)PDCCH), the time-frequency resources for the channel can beassociated with the starting subframes of the channel in respective HARQprocesses. FIG. 16 illustrates an exemplary association of thetime-frequency resources and the starting subframes of HARQ processesfor (E)PDCCH. In this example, the index of starting subframe of PDCCHor EPDCCH repetitions is Q (Q1 and Q2 in FIG. 16 which are integers).When mod(Q1, R)=a1 where R is an integer and may be the number of(E)PDCCH resources in one subframe, then the (E)PDCCH resource is C1.When mod(Q2, R)=a2, then the (E)PDCCH resource is C2. C1 and C2 are the(E)PDCCH resource index, e.g., candidate index or (E)CCE set index inthe (E)PDCCH region. In the figure, the starting subframes of (E)PDCCHHARQ processes #0 and #1 are Q1 and Q2, respectively. When Q1=150,Q2=200, R=100, mod(Q1, 100)=50 and mod(Q2, 100)=0, then (E)PDCCH in HARQprocess #0 will be transmitted in resource C1 (corresponding to a1=50),while (E)PDCCH in HARQ process #1 will be transmitted in resource C2(corresponding to a2=0). It can be seen that although both (E)PDCCHs inHARQ processes #0 and #1 are transmitted in some subframes, they don'tcollide. It is noted that, the way of determining the resource index for(E)PDCCH by the module function can also be applied to other channels,and the way of determining the resource index for a channel in a HARQprocess is not limited to the described module function approach.

According to the third embodiment of the present disclosure, resourcecollision of a channel among different HARQ processes can also beavoided.

It is noted that the above embodiments can be implemented individuallyor in combination unless the context indicates otherwise.

The present invention can be realized by software, hardware, or softwarein cooperation with hardware. Each functional block used in thedescription of each embodiment described above can be partly or entirelyrealized by an LSI such as an integrated circuit, and each processdescribed in the each embodiment may be controlled partly or entirely bythe same LSI or a combination of LSIs. The LSI may be individuallyformed as chips, or one chip may be formed so as to include a part orall of the functional blocks. The LSI may include a data input andoutput coupled thereto. The LSI here may be referred to as an IC, asystem LSI, a super LSI, or an ultra LSI depending on a difference inthe degree of integration. However, the technique of implementing anintegrated circuit is not limited to the LSI and may be realized byusing a dedicated circuit, a general-purpose processor, or aspecial-purpose processor. In addition, a FPGA (Field Programmable GateArray) that can be programmed after the manufacture of the LSI or areconfigurable processor in which the connections and the settings ofcircuit cells disposed inside the LSI can be reconfigured may be used.The present disclosure can be realized as digital processing or analogueprocessing. Further, the calculation of each functional block can beperformed by using calculating means, for example, including a DSP or aCPU, and the processing step of each function may be recorded on arecording medium as a program for execution. Furthermore, when atechnology for implementing an integrated circuit that substitutes theLSI appears in accordance with the advancement of the semiconductortechnology or other derivative technologies, it is apparent that thefunctional block may be integrated by using such technologies.

It is noted that the present invention intends to be variously changedor modified by those skilled in the art based on the descriptionpresented in the specification and known technologies without departingfrom the content and the scope of the present invention, and suchchanges and applications fall within the scope that claimed to beprotected. Furthermore, in a range not departing from the content of theinvention, the constituent elements of the above-described embodimentsmay be arbitrarily combined.

What is claimed is:
 1. A wireless communication method performed by afirst wireless communication device, the method comprising: receivingchannel repetitions of a first channel in multiple subframes from asecond wireless communication device; and performing one of:transmitting channel repetitions of a second channel in multiplesubframes to the second wireless communication device; and receiving ofchannel repetitions of a second channel in multiple subframes from thesecond wireless communication device, wherein a gap between a startingsubframe of the first channel and a starting subframe of the secondchannel is defined and/or configured.
 2. The wireless communicationmethod according to claim 1, wherein the gap between the startingsubframe of the first channel and the starting subframe of the secondchannel is associated with a repetition number defined or configured forthe first channel.
 3. The wireless communication method according toclaim 2, the first channel is control channel to transmit downlinkcontrol information which indicates the repetition number of firstchannel.
 4. The wireless communication method according to claim 1,wherein the gap between the starting subframe of the first channel andthe starting subframe of the second channel is the same in one hybridautomatic repeat request (HARQ) process.
 5. The wireless communicationmethod according to claim 3, wherein the gap between the startingsubframe of the first channel and the starting subframe of the secondchannel is the same as a maximum repetition number defined or configuredfor the first channel.
 6. A wireless communication method performed by afirst wireless communication device, the method comprising: receivingchannel repetitions of a first channel in multiple subframes from asecond wireless communication device in multiple hybrid automatic repeatrequest (HARQ) processes; and performing one of: transmitting channelrepetitions of a second channel in multiple subframes to the secondwireless communication device in the multiple HARQ processes recevingchannel repetitions of a second channel in multiple subframes from thesecond wireless communication device in the multiple HARQ processes,wherein Mx*W=M, where Mx is the number of subframes reserved for one ofthe first channel and the second channel in one HARQ process, M is RoundTrip Time (RTT) for one HARQ process, and W is a positive integer andrepresents the maximum number of HARQ processes within M subframes; andMx*n=N, where N is a gap between starting subframes of the one of thefirst channel and the second channel in two HARQ processes, and n is apositive integer.
 7. The wireless communication method according toclaim 6, wherein each of the first channel and the second channel is acontrol channel, a scheduled channel or a corresponding ACK/NCK channel.8. A wireless communication method performed by a first wirelesscommunication device, the method comprising: receiving channelrepetitions of a first channel in multiple subframes from a secondwireless communication device in multiple hybrid automatic repeatrequest (HARQ) processes; and performing one of: transmitting channelrepetitions of a second channel in multiple subframes to the secondwireless communication device in the multiple HARQ processes; andreceiving channel repetitions of a second channel in multiple subframesfrom the second wireless communication device in the multiple HARQprocesses, wherein time-frequency resources for the first channel indifferent HARQ processes are different.
 9. The wireless communicationmethod according to claim 8, wherein the time-frequency resources forthe first channel are associated with a starting subframe of the firstchannel in each of the HARQ processes.
 10. The wireless communicationmethod according to claim 8, wherein the first channel is PhysicalDownlink Control Channel (PDCCH) or Enhanced PDCCH (EPDCCH).
 11. Awireless communication device, comprising: a receiver, which, inoperation, receives channel repetitions of a first channel in multiplesubframes from a second wireless communication device; and atransceiver, which, in operation, performs one of: transmitting channelrepetitions of a second channel in multiple subframes to the secondwireless communication device; and receiving channel repetitions of asecond channel in multiple subframes from the second wirelesscommunication device, wherein a gap between a starting subframe of thefirst channel and a starting subframe of a second channel is defined orconfigured.
 12. The wireless communication device according to claim 11,wherein the gap between the starting subframe of the first channel andthe starting subframe of the second channel is associated with arepetition number defined or configured for the first channel.
 13. Thewireless communication device according to claim 12, the first channelis control channel to transmit downlink control information whichindicates the repetition number of first channel.
 14. The wirelesscommunication device according to claim 11, wherein the gap between thestarting subframe of the first channel and the starting subframe of thesecond channel is the same in one hybrid automatic repeat request (HARQ)process.
 15. The wireless communication device according to claim 11,wherein the gap between the starting subframe of the first channel andthe starting subframe of the second channel is the same as a maximumrepetition number defined or configured for the first channel.
 16. Awireless communication device, comprising: a receiver, which, inoperation, receives channel repetitions of a first channel in multiplesubframes from a second wireless communication device in multiple hybridautomatic repeat request (HARQ) processes; and a transceiver, which, inoperation, performs one of: transmitting channel repetitions of a secondchannel in multiple subframes to the second wireless communicationdevice in the multiple HARQ processes; and receiving channel repetitionsof a second channel in multiple subframes from the second wirelesscommunication device in the multiple HARQ processes, wherein Mx*W=M,where Mx is the number of subframes reserved for one of the firstchannel and the second channel in one HARQ process, M is Round Trip Time(RTT) for one HARQ process, and W is a positive integer and representsthe maximum number of HARQ processes within M subframes; and Mx*n=N,where N is a gap between starting subframes of the one of the firstchannel and the second channel in two HARQ processes, and n is apositive integer.
 17. The wireless communication device according toclaim 16, wherein each of the first channel and the second channel is acontrol channel, a scheduled channel or a corresponding ACK/NCK channel.18. A wireless communication device, comprising: a receiver, which, inoperation, receives channel repetitions of a first channel in multiplesubframes from a second wireless communication device in multiple hybridautomatic repeat request (HARQ) processes; and a transceiver, which, inoperation, performs one of: transmitting channel repetitions of a secondchannel in multiple subframes to the second wireless communicationdevice in the multiple HARQ processes; and receiving channel repetitionsof a second channel in multiple subframes from the second wirelesscommunication device in the multiple HARQ processes, whereintime-frequency resources for the first channel in different HARQprocesses are different.
 19. The wireless communication device accordingto claim 18, wherein the time-frequency resources for the first channelare associated with a starting subframe of the first channel inrespective HARQ processes.
 20. The wireless communication deviceaccording to claim 18, wherein the first channel is Physical DownlinkControl Channel (PDCCH) or Enhanced PDCCH (EPDCCH).